Dosing hypodermic syringe



March 24, 1953 J. KAS, sR 2,632,445

DOVSING HYPODERMIC SYRINGE Filed Oct. 20, 1951 r a. l l..

Patented Mar. 24, 1953` UNITED STATES PATENT-4N OFFICE; Y ,n `2,632,445! Y A n.

` l i DQSGHY-@DERMIC .SYRNGE'l Kas, Sr., Boston, Applicati'n @grotesca 195i, sensing. 252,353@

This invention relateslto hylpodermic syringe Ivluravinga piston` movable in1 a hollowcylinderzto eject 'the contents of the cylinder...through the needle, and a mechanism operable lto move the piston stepfby-step for. the discharge of accudescription thereof and tothe drawing, of which:

Figure l is an elevational view of a syringe embodying the invention, showing how it is held;

Figure 2 is an elevational view of the same from a different angle and on a larger scale;

Figure 3 is an elevational view, partly broken away to show the parts in section;

Figure 4 is a section on the line 4-4 of Figure 3; and

Figure 5 is an enlarged fragmentary sectional view of some of the parts shown in Figure 3, but in different relative positions.

The syringe illustrated on the drawing includes a cylindrical barrel I having a fitting I2 at one end by which a hollow hypodermic needle I4 can be attached and detached. The barrel I0 may be made of metal with a glass lining I a portion of which shows through an elongated open- Y Figure 3, may be screw threaded into a collar 22 which is threaded on the end portion of the barrel. The head 20 has a central tubular extension 24 through which proiects a piston rod 2S one end of which is attached to a piston 28 slidahly tted within the barrel l0. The piston rod 26 is provided with ratchet teeth 30 which may conveniently be in the form of circumferential grooves extending around the rod so that the rod can operate in any angular position in which it happens to be. A tubular reciprocal member 32 is slidably mounted on the rod 36. this member having a transverse plate 34 from which a short tubular portion 36 extends toward the barrel to telescope with the tubular nroiection 24 from the head 20. A spring 3R is compressed between the head 26 and thel plate 34 so as to press the tubular member 32 constantly away from the barrel I (l. The movement of tubular member 32 away from the barrel is limited by l'any suitable meansfsuch asa bolt 46 screwed into the head 20, the bolt having afhead 42 Whicherigagesgtherouter face of the plate 34, The bolt 40 passes througha hole or notch in therbla'de 34. To cooperate with` the ratchet teeth"` 30 apawl 50 is pivotallym-ounted as at .E2-ina slot Elin the plate Y 34. This pawl isY pressed yieldingly against the rod- 2,6 by a suitable *spring` EGA-The 'slot 554 extends into the bore of themember 32 so as to provide accessfor the pawl 50 tothe rod Arod 26. The tubular extension 24 may be provided with an exterior shoulder 66 thereon to be engaged by the end of the tubular portion 36 on the member 32 to limit its movement when it is pushed toward the barrel. The length of the bolt 40 is selected so that the range of movement of the member 32 is slightly more than the distance from one tooth 30 to the next. Mounted on the member 32 is a thumb piece 68 which is adapted to be pressed by the thumb in the manner illustrated in Figure 1. A reinforcing member 1l) is secured to the plate 34 and the thumb piece 6B to stiften the latter. On the head 20 suitable finger pieces 12 and 14 are provided to be gripped bv the rst two fingers of the hand when the thumb presses on the thumb piece 68. In the embodiment of the invention illustrated on the drawing the finger pieces 12 and 74 are in theform of circular rings but these members may be otherwise shaped if desired.

The detent is provided with a finger piece 16 at its outer end, this being arranged adjacent to the finger piece 58 on the barrel 50 so that both the bolt and detent can be simultaneously swung out against their springs to permit retraction of the rod 26. At the outer end of the rod is a linger piece to facilitate the retraction of the rod when the pawl and the detent are pushed out of engagement with the teeth 30. When the rod. has been retracted, the thumb piece 68 can be pressed repeatedly to cause the piston 28 to move forward by equal steps. If the barrel contains liquid, this will be ejected in successive doses.

When the thumb piece is pressed the pawl 50 which is in engagement with one of the teeth 30 causes the rod 26 and piston 28 to advance until the end of the tubular element 36 hits the shoulder 66. This advance of the rod 26 causes the detent 60 to catch on the next successive tooth 30 so as to hold the rod against retraction when the thumb piece is released to let the spring 38 move the member 32 back to its original position ready for another actuation.

I claim:

1. A hypodermicl syringe comprising a barrel', a piston reciprocable in said barrel, a piston rod extending from said piston out through an end of said barrel, circumferential grooves in said rod forming a series of ratchet teeth, a

tubular member slidable on said rod, means limiting the range of movement of said member relative to said barrel, a spring-pressed pawlv carried by said member and yieldingly held against said rod, a spring pressing said member in a direction away from said piston, and a spring-pressed detentl carried by said barrel and .pressi-ng against said rod.

2; A hypoderinie syringe comprising a barrel, apisrton reciproca-ble in saidI barrel, a hollow needle projecting from one end of the barrel, a detachable,v head on the other end of the barrel,

a piston rod extending fromv said piston out through said head, linger pieces mounted on said head, ratchet teeth on' said rod, a tubular member 1 slidable onsaid rod., means limiting the range'ot movement of said member relative to said barrel, a compression spring between said head and member pressing the member away from the head, a spring-pressed pawl carried by said member and pressed against said rod, and a spring-pressed detent mounted on said head and pressed against said rod.

3. A syringe as in claim l, said tubular member having a thumb-piece to facilitate manual operation thereof.

4. A syringe as in claim 1, said head having a central tubular projection in telescoping relation with said tubular member.

5. A syringe as in claim 1, said pawl and detent having projections located in juxtaposition to facilitate simultaneous movement of said pawl and detent out of engagement with said ratchet teeth to permit retraction of the piston and rod.

JOHN L. KAS, SR.

REFERENCES CITED The following references are of record in the file of this patent:

UNTED STATES PATENTS 

